﻿#define _CRT_SECURE_NO_WARNINGS

#include<stdio.h>

int main(){
	int arr[10] = { 1,2,3,4,5,6,7,8,9,10 };
	int n = 0;
	int flag = 0;
	scanf("%d", &n);
	int left = 0;
	int right = sizeof(arr) / sizeof(arr[0]) - 1;
	while (left <= right) {
		int mid = (left + right) / 2;

		if (arr[mid] > n) {
			right = mid -1;
		}
		else if (arr[mid] < n) {
			left = mid + 1;
		}
		else {
			printf("找到了，下标为%d\n", mid);
			flag = 1;
			break;
		}
	}
	if (flag == 0) {
		printf("找不到");

	}
}

